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Leichhardtia sisurnius (Hedley, 1918)

Diagnostic features

Snails having small sinistral subglobose shells with unshouldered whorls; spire low, whorls rounded;  aperture elliptical, parietal lip gently curved, parietal callus adheres to body whorl; anterior end of the aperture constricted which sometimes forms a short canal, umbilicus present. Body whorl traversed by spiral rows of striae and wrinkles which bear periostracal hairs in living specimens. Copulatory organ lacking accessory bursa or flagellum, pendant penis uniramous with lateral pore. Prostatic duct present, rectal ridge absent.

This species is readily recognised by the shell surface microsculpture consisting of fine raised points commonly coalescing into continuous wavy lines and  the constricted anterior end of the aperture which sometimes forms a short canal.

Classification

Leichhardtia sisurnius (Hedley, 1918)

Class Gastropoda

Subclass Heterobranchia

Order Hygrophila

Superfamily Planorboidea

Family Planorbidae

Genus Leichhardtia Walker, 1988 (Type species: Bullinus sisurnius Hedley 1918).

Original name: Bullinus sisurnius Hedley, 1918. Hedley, C. (1918). Narrative of an expedition of exploration in North Western Australia by Herbert Basedow. Special Report. Mollusca. Transactions of the Royal Geographical Society of Australasia 18: 263-283, pl. 41.

Type locality: Paterson Range, Western Australia.

Biology and ecology

On water weeds, wood etc., in ponds, billabongs, swamps and sluggish streams and rivers. Feeds on algae and detritus. Egg mass typically a bean(kidney)-shaped jelly strip containing many small eggs. Development direct.

Additional information on the biology and ecology of members of this family can be found in Fauna of Australia, vol. 5B, p. 1072-1074.

Distribution

Gulf of Carpentaria and Timor Sea divisions, northern parts of NW Queensland, Northern Territory and Western Australia.

Notes

The shell surface microsculpture of fine raised points which often coalesce into continuous wavy lines is characteristic as is the constricted anterior end of the aperture which sometimes forms a short canal.

Further reading

Baker, F. C. (1945). The molluscan family Planorbidae. Urbana USA, University of Illinois Press.

Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.

Hubendick, B. (1955). Phylogeny of the Planorbidae. Transactions of the Zoological Society of London 28: 453-542.

Walker, J. C. (1988). Classification of Australian buliniform planorbids (Mollusca: Pulmonata). Records of the Australian Museum 40: 61-89.